Pet containers with enhanced thermal properties

Abstract

The present invention provides a blow molded heat set PET container having enhanced thermal properties and a first glass transition temperature and a second endothermic transition temperature substantially higher than the glass transition temperature.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field[0002]This invention relates to PET containers having enhanced thermal properties and methods for making the same.[0003]2. Background Art[0004]Blow molding processes for forming PET containers are well known in the art. Blown PET containers have replaced metal and glass containers in numerous food storage applications such as carbonated soft drinks and lower temperature filled food products such as peanut butter and mayonnaise. However, prior art PET containers have not replaced metal and glass containers for product storage and processing applications where the container is filled or heated to temperatures above 97° C. (207° F.) as such containers experience significant shrinkage, deformation rendering the container unuseable. Additional in-roads into the replacement of glass is desired in food processing applications such as low-temperature pasteurization, high-temperature pasteurization and retort. Low temperature pasteurization ...

AI Technical Summary

Benefits of technology

[0021]The present invention further provides a blow molded heat set PET container having enhanced thermal properties wherein the X-ray diffraction pattern has at least five crystalline peaks.

[0022]The present invention further provides a blow molded heat set PET container having enhanced thermal properties having a crystallinity less than about 30% and a density of greater than about 1.37 g / cc.

[0023]The present invention further provides a process for forming a heat set PET container with enhanced thermal stability including: (1) inserting a preform into a blow mold; (2) blowing the preform into a container having an inner surface and an outer surface and a sidewall having variations in wall thickness along an axial dimension with thinner wall portions and thicker wall portions; (3) selectively cooling predetermined portions of the inner surface by directing a flow of cooling fluid with the thicker wall portions receiving more cooling fluid than the thinner wall portions; and (4) removing the container from the blow mold when the container has sufficiently cooled to be self-supporting and further cooling the container outside the mold.

[0024]The present invention further provides a process for forming a heat set PET container with enhanced thermal stability including: (1) inserting a preform into a blow mold; (2) blowing the preform into a container having an inner surface and an outer surface and a sidewall having variations in wall thickness along an axial dimension with thinner wall portions and thicker wall portions and maintaining the blown bottle in the mold at a temperature within the range of 160-200° C. for a period from two to twenty seconds; (3) selectively cooling predetermined portions of the inner surface by directing a flow of cooling fluid with the thicker wall portions receiving more cooling fluid than the thinner wall portions; and (4) removing the container from the blow mold when the container has sufficiently cooled to be self-supporting and further cooling the container outside the mold.

[0025]The present invention further provides a process for forming a heat set PET container with enhanced thermal stability including: (1) inserting a preform into a heated blow mold; (2) blowing the preform into a container having a sidewall with an inner surface and an outer surface, the sidewall having variations in wall thickness along an axial dimension with thinner wall portions and thicker wall portions; (3) maintaining thinner wall portions at a first temperature and thicker wall portions at a second temperature lower than the first temperature and selectively cooling predetermined portions of the inner surface by directing a flow of cooling fluid with the thicker wall portions receiving more cooling fluid than the thinner wall portions; and (4) removing the container from the blow mold when the container has sufficiently cooled to be self-supporting and further cooling the container outside the mold.

[0026]The present invention further provides a process for forming a heat set PET container with enhanced thermal stability including: (1) inserting a preform into a heated blow mold; (2) blowing the preform into a container having a sidewall with an inner surface and an outer surface, the sidewall having variations in wall thickness along an axial dimension with thinner wall portions and thicker wall portions and maintaining the blown bottle in the mold at a temperature within the range of 160-200° C. for a period from two to twenty seconds; (3) maintaining thinner wall portions at a first temperature and thicker wall portions at a second temperature lower than the first temperatures and selectively cooling predetermined portions of the inner surface by directing a flow of cooling fluid with the thicker wall portions receiving more cooling fluid than the thinner wall portions; and (4) removing the container from the blow mold when the container has sufficiently cooled to be self-supporting and further cooling the container outside the mold.

Problems solved by technology

The most common experimental error would have caused all of the peaks to shift by the same amount.

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